The Regular and the Rule in Architecture.

This letter from the editor presents Vol. 25(2) of the Nexus Network Journal. This issue has two connected themes, the first is about the role of regular modules, patterns, or proportions in architecture, and the second, the ways rules or systems underpin architectural form. The papers in this issue address either regularity, rules, or in most cases, both, because spatial and formal patterns are typically derived from rules. Collectively, the eleven research contributions in this issue have topics that span chronologically from the thirteenth century to the present day, and geographically from Asia to Africa and Europe. [ABSTRACT FROM AUTHOR]